The use of tapered containers in the canning industry has always been desirable, although tapered cans have not been widely used. An important advantage of tapered cans over straight cylindrical cans is the ready nestability of the former enabling compact storage of can bodies with stability in a much smaller storage area. Cylindrical can bodies not only resist nesting but cannot be stacked with any degree of stability, and therefore require a much greater storage area. The daily shopper in the supermarket is also very familiar with the tendency of stacked cylindrical canned goods to tumble and scatter on shelves. Conically tapered containers are much more readily stackable with stability on store shelves due to the fact that the smaller diameter container bottoms will stack and nest nicely on the larger diameter tops of containers below.
In spite of these advantages present in tapered containers, certain drawbacks in their commercial usage has prevented them from being widely adopted, as stated. Chief among these drawbacks is the much greater difficulty in applying labels to the conically tapered walls of tapered cans or other containers. Tapered containers require the use of curved labels in which one edge of the label must be somewhat longer than the other edge to match the two different circumferences of the container near its opposite ends. On a production basis utilizing high speed labeling machinery, it has not proven to be possible to apply labels to tapered cans and the like with the necessary consistency in terms of good final appearance demanded in the industry. The main problem which has not been solved is that of obtaining good alignment or registration of the two ends of a curved label being applied to the periphery of a tapered can. Misalignment of the label ends seems to inevitably result in the prior art, and good-appearing labels are so important that there is a major reluctance to use tapered can bodies in the industry.
Attempts have been made to deal with the problem in the prior art, and U.S. Pat. No. 3,915,338 is one example. In this patent, curved labels for use on tapering container bodies or necks are held within a special arcuate tray carrier. The stacked labels in the curved carrier are disposed vertically on edge within the labeling apparatus. The labels are also held within the stack in a flat non-twisted configuration. As a result, the patented method and apparatus simply has not given the results hoped for in terms of applying labels to tapered containers with the necessary accuracy and consistency. Therefore the need for this accomplishment still exists and still remains unsatisfied in the art. Accordingly, it is the objective of the present invention to completely satisfy this need through the provision of a highly efficient and reliable production apparatus and method for labeling tapered cans and the like.
The essence of the present invention resides in positioning and configuring the curved labels at a container labeling station in such a manner that oncoming rotating tapered cans having glue applied to their peripheries will each in succession pick up a leading label from a stack and cause the label to be wrapped around the tapered wall of the can with the leading and trailing ends of each label in precise registration.
More particularly, in the present invention, the labels are held in a longitudinally twisted form in the labeling apparatus. The leading ends of the labels which are initially engaged by oncoming containers are vertically disposed and the trailing ends of the labels are inclined so that their top edges project forwardly of their bottom edges. The label inclination angle progressively increases from the vertical leading end to the trailing forwardly inclined end. The labels are also held in a curved state between their leading and trailing ends so that their intermediate portions are disposed rearwardly from the label ends. This particular label configuration is critical and necessary to achieve on a production basis the desired results in terms of precise and consistent labeling of tapered cans and the like. The required configuring and holding of the labels within the labeling apparatus is achieved by using a contoured pusher block behind the label stack in conjunction with a system of top and bottom edge adjustable knives at the front of the stack which shape and hold the forwardmost labels in the stack with precision while permitting their clean individual withdrawal by containers passing the labeling station.
Other important features and advantages of the invention will become apparent to those skilled in the art during the course of the following detailed description.